alpha cb24 hot water problem

[grimmonkey]

Just read through all the posts on the this subject and reckon the problem might be the diaphragm but no-one has described how my boiler has deteriorated.
It started with my boiler only giving hot water when the central heating was switched on. The central heating is fine. At this time the water was coming out as hot as ever. over the last 4 or 5 weeks, it has become harder and harder to get any hot water and the temperature has been decreasing as the weeks went on. Getting any hot water involved switching all the hot taps on in the house and then switching them off on at a time. I now have no hot water at all.
I have removed the heat exchanger and descaled it. There wasn't much buildup anyway. I have removed the diverter and cleaned but have yet to touch the diaphragm as I haven't got a replacement with all the required seals. I have taken the flow switch off and pressed in manually. This fired the boiler up even when the boiler was switched to hot water only, but instead of hot water I got central heating.
So, diaphragm or something else. The fact that it has deteriorated over a period of weeks suggests something mechanical as opposed to switches or electronics, but I don't know how a diaphragm works so I can't be sure.
Any advise would be truly appreciated.

Andy

 

[Rob]

yes it sounds like a diaphragm failing. when the diaphragm lifts aswell as making the microswitch it also alters the flow of water around to the HW. hence why manually pressing the micro switch gave you CH

the diaphragm is like £1 and seals itself. not too sure on which model alpha yours is but if its located to the front left its about 10 mins work. bout 30 mins if its located centrally inside.

rob

 

[grimmonkey]

Cheers rob. I'll pick one up monday morning. There's something to be said for a cold shower in the morning but the choice would be nice.

 

[Paul Barker]

I would change the flow switch also as the early ones are temperamental and the new ones are fine. It would be false economy not to.

If you have black grey or white thermisters all well and good. If you have any other colour I would also recommend changing both. You will probably be supplied with white, these are of great quality. This is not related to your fault but as you have to drain the boiler anyway and thermisters are relatively cheap, again it would be false economy not to fit the very best, which over the years Alpha has distilled to these white ones from experience. I repeat there have been no problems with the black or the grey ones.

 

[ChrisR]

like £1

A kit, more like £25

 

[Rob]

like £1

A kit, more like £25

really? thats extortionate!